Detrimental effects of lipopolysaccharide on the attachment and outgrowth of various trophoblastic spheroids on human endometrial epithelial cells

Abstract

Objective: Lipopolysaccharide (LPS) from Gram-negative bacteria causes poor uterine receptivity by inducing excessive inflammation at the maternal-fetal interface. This study aimed to investigate the detrimental effects of LPS on the attachment and outgrowth of various types of trophoblastic spheroids on endometrial epithelial cells (ECC-1 cells) in an in vitro model of implantation.Methods: Three types of spheroids with JAr, JEG-3, and JAr mixed JEG-3 (JmJ) cells were used to evaluate the effect of LPS on early implantation events. ECC-1 cells were treated with LPS to mimic endometrial infection, and the expression of inflammatory cytokines and adhesion molecules was analyzed by quantitative real-time polymerase chain reaction and western blotting. The attachment rates and outgrowth areas were evaluated in the various trophoblastic spheroids and ECC-1 cells treated with LPS.Results: LPS treatment significantly increased the mRNA expression of inflammatory cytokines (CXCL1, IL-8, and IL-33) and decreased the protein expression of adhesion molecules (ITGβ3 and ITGβ5) in ECC-1 cells. The attachment rates of JAr and JmJ spheroids on ECC-1 cells significantly decreased after treating the ECC-1 cells with 1 and 10 μg/mL LPS. In the outgrowth assay, JAr spheroids did not show any outgrowth areas. However, the outgrowth areas of JEG-3 spheroids were similar regardless of LPS treatment. LPS treatment of JmJ spheroids significantly decreased the outgrowth area after 72 hours of coincubation.Conclusion: An in vitro implantation model using novel JmJ spheroids was established, and the inhibitory effects of LPS on ECC-1 endometrial epithelial cells were confirmed in the early implantation process.

Evaluation of Lipopolysaccharide and Interleukin-6 as Useful Screening Tool for Chronic Endometritis

“…Our findings were consistent with those of other studies, which showed that the expression of proinflammatory cytokines, such as IL-6 and IL-1β, was significantly higher in menstrual effluent patients with CE [14]. IL-6 is a well-known inflammatory marker of LPS [10,21], and IL-6 has also been shown to be a useful diagnostic marker for endometriosis, which is a chronic inflammatory disease [22].…”

“…LPS administration causes extensive inflammatory macrophage infiltration of uterine tissue, and it also increases the expression of Il-1β, Tnfα and other genes in mice [13]. In humans, LPS affects the trophoblastic spheroids and endometrial epithelial cells and decreases uterine receptivity [14]. On the other hand, few human studies have reported that LPS is related to endometrial inflammation, which has been associated with infertility and repeated implantation failure [1].…”